Continued refinement and fitting of the 2A resolution structure of bovine Cu, Zn superoxide dismutase. Processing of native (to 3A resolution) and derivative film data for human liver Mn superoxide dismutase, further data collection, and hopefully solution of heavy atom derivatives. Data collection and processing for the rhombohedral crystals of chicken liver sulfite oxidase. Fitting and refinement of the Root Effect hemoglobin from the spot, starting with electron density maps phased by our current rotation function results. Continuation of our analyses of general features of protein structure, including application of those generalizations to the interpretation of low-resolution x-ray results.